Atomic layer deposition of ruthenium thin films from Ru(thd)3 and oxygen

Ruthenium thin films were grown by atomic layer deposition (ALD) from tris(2,2,6,6-tetramethyl-3,5-heptanedionato)ruthenium [Ru(thd)(3)] and oxygen, at temperatures between 325 degreesC and 450 degreesC. All the films were polycrystalline metallic ruthenium as analyzed by X-ray diffraction (XRD). Impurity contents of the films (<2.9 at.-% H, <1.9 at.-% C, and <5.5 at.-% O) were nearly independent of the Ru(thd)(3) pulse time as analyzed by time of flight elastic recoil detection analysis (TOF-ERDA). The films had resistivities below 20 muOmega cm and they adhered well to a thin Al2O3 film on glass. Growth rates of 0.36 Angstrom per cycle were obtained at a deposition temperature of 350 degreesC. The gaseous reaction by-products were analyzed in situ by quadrupole mass spectrometry (QMS).